public class Circle {
    private double radius;
    private double area;
    private double circumference;

    public Circle(double radius)
    {
        this.radius = radius;
    }
    public double getCircle()
    {
        System.out.println("半径：" + radius);
        return radius;
    }
    public double calculateArea(){
        area = Math.PI * radius * radius;
        System.out.println("面积：" + area);
        return area;
    }
    public double calculateCircumference(){
        circumference = 2 * Math.PI * radius;
        System.out.println("周长：" + circumference);
        return circumference;
    }
    public static void main(String[] args){
        Circle circle = new Circle(3.0);
        circle.getCircle();
        circle.calculateArea();
        circle.calculateCircumference();
    }
}
